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doubler "?" NP241/NVG271

Except then you might as well have a 205 since the weight would be lower.....
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But I still don't get the extra reduction.


Thanks for help everyone, time to start thinking again. I may just be back in the market for a '78-79 Ford front... Anyone want to discuss that NVG271?

And I think I'm going to retitle the post so its more discriptave.
 
Eh, if you've got an auto I'd have no problem running a range box in front of a 241. If you've got a manual (465) you're already pushing the rated input limits of the 208-241. Hard use (drop the clutch) and high traction will be taxing it. With an auto, I don't think it'd matter much. You're not seeing the "drop the clutch" and you have less raw torque multiplication (torque converter takes the hard link between motor and terrain and softens it).

The things that worry me about the 208-241 are the front output (the bearings mostly, especially the rear bearing) and the selector collar. The one that switches the ranges I think is probably strong enough. I'm kind of leary of the one that engages the front output. As long as you're running a Chevy 208 or 241 the chain and sprockets should be plenty strong.

I haven't actually had a 241HD or a 271 apart yet. The HD is just supposed to have a wider chain. I don't know anything about the 271.

NorthWestFab said:
You're correct, I have a NP203/NP241 Adaptor kit coming out in the next few weeks, its just hard to find time to get new products fitted into the production schedule. Price is the same, 699 for the kit.

-Kyle
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What about a 241/205 kit? I have a driver drop 32 spline NV241 just itching to go in my wheeling rig with a Chevy 205 behind it. Low range in reverse sucks now because it's too low. You can't get any wheelspeed. With a 205 I could get quite a bit more.
 
Are you talking about using the planetary set from the 241? Want to explain or send me a link where I can read up on this. It sounds intresting but I don't understand how it gets mounted. There are a LOT of IFS 241s out there.
 
Well, you could cut the 241 case and just use the front part and make a plate for the gaping hole in the side. You really only need like the first 8" for the range selection part. It's common for Ford guys to cut a BW 13-56 and run a NP205 behind them. You can search for that if you want.

What I'm saying to do is to just run the driver drop 241 case in its entirety. Keep the front output. You could use it to run a PTO pump. Just make an adapter to bolt on to the back case halve. It'd require the manufacturer of the adapter to make a new bearing support though. It'd still be a pretty short range box.
 
The petersen's UA truck now has a ferd 205 in it because the 271 was too wide to fit in the frame rails.
At some point you have to worry about the housing integrity on the 241s. The just were not built to have the torque output on the front that we can get with a D60F and bit tires.
Really what it comes down to is your acceptable frequency of breakage, consequences of the breakage and how hard you drive.
 
Stephen said:
The petersen's UA truck now has a ferd 205 in it because the 271 was too wide to fit in the frame rails.
At some point you have to worry about the housing integrity on the 241s. The just were not built to have the torque output on the front that we can get with a D60F and bit tires.
Really what it comes down to is your acceptable frequency of breakage, consequences of the breakage and how hard you drive.
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If you're not using the front output then it's not a problem.

The 271 will fit in most vehicles because our frames are narrow due to the tanks being outside of the framerails. In fact, it'll probably fit in a K5 frame because the frame was a little wider than pickups. All the pickups with the inboard gas tanks have wide frames. IFS Chevy frames are 3" wider.

I have faith in the 271 because you're only doubling the input torque with a 203 range box. With an auto it would barely even know it compared to a 1000ftlb diesel weighing 8500lbs doing tractor pulls and sticky tire launches at the dragstrip in 4wd with a 5600 in front of it. It'd probably be iffy wheeling with a manual due to the fact that a 400ftlb motor with a sizeable rotating mass isn't going to want to stop when it gets traction.

The BW 13-56 used in Fords starting in 88 is a beefy case that is known to take a lot of abuse. I suspect the 271 is comparable.
 
Alright. Enough with the hogwash. The late model chain driven t-cases are quite strong, and in some cases stronger than everyones beloved NP205. New Venture Gear has a website that gives the specs on all their late model t-cases, except the NVG241OR (Rubicon case) which is still quite new. The site is down as of right now but I'll throw out what I remember. These specs should speak volumes about how enormous the NV271 is compared to the smaller cases.

NV271 has a 17,500 lb GVW rating!!!! (I know this for sure).
NV241 has GVW rating somewhere around 9000.
NP231 has an anemic GVW rating around 5000.
The larger cases (241, 261, 271) have nearly a 3 quart capacity.
The smaller cases are closer to 1.5 quarts.
The NV271 weighs in at around 140 lbs!!!!
The NP231 weighs in at 87 lbs (I also know this for sure).

So in closing, the NV241 is quite strong and I have no problem running it, yet I can understand some people's reservations about it. The line of irrational fear has to be drawn when questioning the stregnth of something as mamoth as the NV271. Come on now. 140lb case with a 17,500lb GVW rating living just fine behind monster torque diesels, many of which have been outfitted with much larger tires. Re-evaluate your fears and quit worrying about it.
Travis
 
Yes the 241 by itself is awsome, and extremely strong. i would run one any day, but thats not the point. I just dont think it can survive after the input power has just been doubled. Theres twice as much force on it then before, its just not going to handle that power as dependibly as a 205 would.
 
Eh, more important than the physical weight or the GVW rating of the case is the actual input torque rating of the case. The regular 241 is rated for 1500ftlbs of continuous input torque.

Shock loading and system bind is what concerns me the most.
 
np241 tech

the non HD 241 is rated at 5500 lb ft, with a gvw of about 9000 lbs. i've beat on mine for 220k miles so far and no problems yet. i also just had it apart to do the JB SYE and it looked perfect inside.
 
All this tire smoking front end torque in a truck that comes with a notoriously fragile IFS CV drive system? (referring to the 241 of course). I guess in the dodge trucks they come with 30 spline D60 fronts.

I'll keep my 205 for tires over 38", thanks.

The 271 is a brute, I know the one in the ultimate SD has broken lots of stuff. No matter what they don't have front wheel drive, so there!

K5 frames are the same width as the truck frames up to '81, then they splay out a little bit but it's not a whole lot. From discussions on the UA truck, it wasn't even close to fitting, in fact the memorable quote was "I think the clearancing would consist of a window THROUGH the frame."
 
IFS isn't all that fragile, especially the modern 1 ton stuff. They still don't like maddening wheelspin at full lock when it gets traction but neither does a D60.

If the 241 was so fragile they wouldn't put it behind big motors that generate a lot of torque or under vehicles that weigh a lot and can carry a lot.

They put its predecessor, the 208, in 5/4 ton trucks with a front limited slip.

If it was obnoxiously weak they'd have never put a front 32 spline output on it.

No, it doesn't have FWD, that's for sure. But the 205 doesn't have a 2.72:1 low range either. I probably would be leary about putting a 241 with a range box in front of it if I had a manual transmission. Otherwise, I see no real issues with it. I think the hot setup would be to have a 241 in front of a 205. Can still have FWD, low range RWD, and you have two low ranges and one insane low range. That's like 5.3something to 1 low range.
 
Luckily, someone thought of putting a 241 in front of just about anything, they call it a Klune.
and charge a bunch of money for it.
 
CyberSniper said:
...If the 241 was so fragile they wouldn't put it behind big motors that generate a lot of torque or under vehicles that weigh a lot and can carry a lot...

...If it was obnoxiously weak they'd have never put a front 32 spline output on it...

...No, it doesn't have FWD, that's for sure. But the 205 doesn't have a 2.72:1 low range either...
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All I can say is AMEN BROTHER!!!!
Travis
 
This is some great discussion.
2 doubler manufacturers and lots of opinions...

The 241 explosion stories I've heard have been in heavier vehicles with bigger tires but NOT the bigger motors.
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Stephen, have you ever seen a 241 (or a 271) break firsthand?

Has anyone here seen a 241 fail mechanically firsthand? (not from case impact)

Has anyone here ever doubled the input on a 241 and broke it?

(Subtopic)
Recently, I had the chance to drive a Sniper with a C6/Atlas combo and was shocked to find out how hard it is to actually get it into Front Wheel Drive Only.
I liked using it but seemed like a lot of effort...

Also, a friend of mine runs a C6/Klune-V/205 in an EB.
When I rode with him, he also had some trouble finding Front Wheel Drive Only.
Is this true with every case/situation?
 
Look guys, 241's a 208's don't fall apart when you go offroad. They're good cases, but how many people on here have exploded 208's? That's pretty common, even when it's just stuff like blowing unexplained chunks out of the case. They are pretty good but they're not a cast iron gear drive case. And let's put the military CUCV K30's in perspective here: they came with a HD 6.2L that puts out 150hp and ran smooth 32" tires. They were the civilian equivalent of a contractor or farmer's work truck, not a HD 4wd vehicle.
241's are a step up from the 208's but I have sold Doublers to people who broke them. One I remember in particular went through 2 of them in a sub with 38's before he stepped up.
The 271 is a whole different story, they are massive with a huge torque capacity. Whether or not they have a matching front drive capacity we don't know and probably will never will since they can't run in front only. The rear output shaft in a 271 makes the 205 look pretty wimpy.
No matter what, any chain drive front end is going to eventually stretch the chain and wear the sprockets. Especially under high front torque loads. In a gear drive case, sometimes you have to change the oil. The front drive system is really durable, not perfect, the bearings and front output shaft can wear, but it's very durable.

These alum. cases are just different tools for different jobs, you don't use a 3/4" drive ratchet for everything, nor is the underdriven 205 right for everything. If you know the limits of your vehicle and don't exceed them, you'll be fine. How many guys get by with 1/2T axles in trucks with big tires? LOTS. Do they do the stuff I do? Guarateed not. Do they do what they want to do? Probably so.

You should keep some physical characteristics in mind when choosing:
Length: 205 is only 12.5" or so front to ujoint CL, even a SYE 241 is several inches longer. I'd have to measure a 271 but they're pretty long even with the factory fixed output.
Width: 241's not really an issue but the 271 is huge and probably won't fit well in a early GM frame.
Case toughness: the 205 will be much more tolerant of external forces, not matter how you slice it. Even things like driveshaft bind will be dealt with much more gracefully.
Weight:205's the big loser here, obviously. Probably by 50# or so over a 241. The 271 isn't much lighter if any.
Gear ratio: any of the alum case win if you want lower gears. For some, the 2:1 and 4:1 are perfect. In my case, I'd have to look at changing the trans and axle gearing to make use of anything deeper in the T-cases since I'm happy with what I have.
Front wheel drive ability: 205 has it, others don't. Rear wheel low range falls into this catagory also.

About shifting into front drive: remember you're really shifting OUT of rear wheel drive when you do this and if you have a locker, it's going to be bound up which makes it a pain no matter what. With a selectable locker, it often helps if you unlock the locker, wiggle just a little, then try to shift. If nothing else you'll look funny wiggling then shifting. :-)
I'm going back to work now, I think this has been hashed.
 
yeah, I'm thinking that 241s are more useful for supplying planetaries for aftermarket Klune-style reduction units than anything else. There is supposedly a couple of guys/groups over on pirate trying to produce such a unit in the sub-$1500 price range. That'd be pretty cool... 2.72 on top of the 1.96 of the 205 would be a good amount gear. I like things with cable shifters too. ;)

j
 
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